Field of the Invention
The present invention relates to protective and lubricating coatings for metals and more particularly to compositions for applying a dry protective and lubricating surface coating to firearms and ammunition.
It has long been recognized that bullets frictionally engage the bore of the firearm through which they are fired. This heats the barrel. Small surface defects in the barrel increase frictional forces and remove particles of the bullet. The lead or copper deposits build up in the barrel and impair ballistic operation of the weapon. The problem has been addressed by many inventors and various lubricants including waxes, greases, soaps have been applied to the bullet and the firearm with varying degrees of success. Oils and greases have the added advantage of corrosion inhibition when applied to the weapon.
One problem with oils and greases is that they tend to collect and hold foreign matter including abrasive dust that is especially harmful to the weapon. Coatings that include organic matter such as waxes and resins may leave behind harmful products from the breakdown of the organic matter at the extreme temperature and pressure encountered.
It is well established in the art of lubricants that molybdenum disulfide is a most effective dry lubricant that is resistant to high temperature and pressure.
Martin in U.S. Pat. No. 4,454,175 issued 6/24/84 teaches that in order to effectively coat metal surfaces with molybdenum disulfide without an organic binder, the bullets must be tumbled for hours with the powder, steel shot and fibrous matter which gradually burnishes a thin, adherent coating of the molybdenum sulfide on the bullets.
Vatsvog in U.S. Pat. No. 4,196,670 issued 4/8/80 teaches the use of a synthetic resin dissolved in an organic solvent in which the molybdenum disulfide is suspended. When a bullet is coated, the solvent evaporates and the resin holds the molybdenum disulfide on the surface.
Gregg in U.S. Pat. No. 4,731,189 issued 3/15/88 teaches a coating and method combining molybdenum disulfide, petroleum and silicone oils, metallic soap greases, graphite and beeswax.
A composition that will protect the metal parts of a weapon, that will prevent build up of materials wiped off the bullet, that will provide lubrication in the harsh environment of the firing of the weapon and that will not itself leave harmful deposits is not known to be characterized by the compositions of the prior art.